NEW YORK (AP) Federal authorities said Friday they are investigating claims that Martin Shkreli has been running his pharmaceutical company from behind bars using a contraband smartphone.

The U.S. Bureau of Prisons told The Associated Press it has opened an inquiry into whether the man nicknamed the Pharma Bro violated prison rules forbidding inmates from conducting business and possessing cellphones.

Shkreli, 35, is serving a seven-year sentence for securities fraud at the Federal Correctional Institution at Fort Dix, New Jersey, a low-security prison complex about 40 miles (65 kilometers) from Philadelphia. He was found guilty of lying to investors in two failed hedge funds and cheating them out of millions.